In common Pay-TV decoding units (also known as Set-top-box), the decoding unit comprises a slot to insert a security module (generally in the form of a smart card). The handling of the rights, the decryption of the keys to access the content is carried out in such security module.
Those security modules can be implemented in a variety of manners such as on a microprocessor card, on a smartcard or any electronic module in the form of a badge or key. These modules are generally portable and detachable from the decoding unit.
The most commonly used form has electrical contacts but contactless versions of type ISO 14443 also exist. Another implementation of the security module exists where it is directly soldered inside the decoding unit, a variation of this being a circuit on a socket or connector such as a SIM module. Yet another implementation is to have the security module integrated on a chip which has another function e.g. on the de-scrambling module or on the microprocessor module of the decoding unit. The security module can also be implemented in software.
The decoding unit could have peripherals such as remote control, external hard disk, conditional access module (such as provided by SmarDTV™) or security elements connected via USB, PCMCIA, ISO7816 or Bluetooth. Those peripherals interact with the decoding unit and contain identification data.
Some decoding units do not contain a security module and the security operations are carried out directly by the software—protected or not by so called SW protection techniques such as code obfuscation and/or White-Box Cryptography—of the decoding unit. In such a case, the decoding unit regularly initiates a connection with a management center to receive the keys to descramble the audio/video content. This connection can be made via a modem or via IP (Internet) connection.
In the case that no such connection is available, the security relies only on software verification of the rights carried out by the decoding unit.
The temptation is great to acquire a general purpose decoding unit and load into it a modified version of the software that skips the verification of the rights.
The aim of the present application is to offer a better way to secure the audio/video content received by a decoding unit.